given two parallel lines $P$, $Q$ and two points $X$,$Y$ how to construct a rhombus $ABCD$ passing through $X$,$Y$ and opposite sides lie on $P$ and $Q$.
I solved a special case of this problem where one point $Y$ lies on the parallel line. any hints or ideas?
If $Y$ lies on line $q$, draw a circle with center $Y$ and radius $XY$. The circle will intersect line $p$ at point $Z$. If I draw a perpendicular bisector of $ZX$ it will intersect line $p$ at $B$. Then it is easy to construct the required rhombus.

